What is the actual quality of machine translations?
Who claimed that machine translation is as good as a human translator? For me, as a professional translator who makes his living on translation for 35 years now, MT means that my daily production of human quality translation has grown by factor 3 to 5, depending on complexity of the source text.

I cannot agree that the quality of MT goes down with the length of the foreign language input. That used to be true for the old systems with semantic and grammatical analyses. I don't think that I know all of the old systems (I know Systran, a trashy tool from Siemens that was sold from one company to the next like a Danaer's gift, XL8, Personal Translator and Translate), but even a professional system in which I invested 28.000 DM (!!!!) failed miserably. 

For example, the sentence: 


  On this hot summer day I had to work and it was a pain in the ass.


can be translated using several MT tools to German.

Personal Translator 20:


  Auf diesem heißen Sommertag musste ich arbeiten, und es war ein Schmerz im Esel.


Prompt: 


  An diesem heißen Sommertag musste ich arbeiten, und es war ein Schmerz im Esel.


DeepL: 


  An diesem heißen Sommertag musste ich arbeiten und es war eine Qual.


Google: 


  An diesem heißen Sommertag musste ich arbeiten und es war ein Schmerz im Arsch.


Today, Google usually presents me with readable, nearly correct translations and DeepL is even better. Just this morning I translated 3500 words in 3 hours and the result is flawless although the source text was full of mistakes (written by Chinese).